291648281 has 2 divisors, whose sum is σ = 291648282. Its totient is φ = 291648280.

The previous prime is 291648223. The next prime is 291648323. The reversal of 291648281 is 182846192.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 255840025 + 35808256 = 15995^2 + 5984^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-291648281 is a prime.

It is a super-2 number, since 2×291648281² = 170117439620509922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (291641281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145824140 + 145824141.

It is an arithmetic number, because the mean of its divisors is an integer number (145824141).

Almost surely, 2^291648281 is an apocalyptic number.

It is an amenable number.

291648281 is a deficient number, since it is larger than the sum of its proper divisors (1).

291648281 is an equidigital number, since it uses as much as digits as its factorization.

291648281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 41.

The square root of 291648281 is about 17077.7129909130. The cubic root of 291648281 is about 663.1622662386.

The spelling of 291648281 in words is "two hundred ninety-one million, six hundred forty-eight thousand, two hundred eighty-one".